Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Built a scanner? Started to build a scanner? Record your progress here. Doesn't need to be a whole scanner - triggers and other parts are fine. Commercial scanners are fine too.
jakegaisser
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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by jakegaisser » 13 Mar 2010, 02:27

I will take a nice close up with better lighting of the skate board wheel assembly. We ended up ditching the foot lasso... the height of the table does not allow for enough movement range of the lasso. We upped the weight to about 8 pounds total and just tightened up the bolts on the platern, it is now working pretty smoothly!! :mrgreen:

It will be even better when we can ditch the push button with an automatic sensor. and also power the cameras and usb remote with a direct power supply instead of batteries. we have already had to switch out the camera batteries a few times and we have only scanned 1 book and done some testing.


ONE ISSUE WE ARE HAVING, we cannot just press and release the picture taking button, we have to hold it for a sec and then release.... I believe this is due to the auto focusing that I have read about, but I am not certain. the dial for our A470 powershot has playback, auto shoot, manual shoot. we have it on manual... but it still gives the initial beep before the camera shoot as if it is focusing. Sometimes one of the cameras does not fire, or the other camera fires twice, this does not happen often, but it sure is annoying! :evil:

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daniel_reetz
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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by daniel_reetz » 13 Mar 2010, 09:56

are you using SDM/CHDK?

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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by jakegaisser » 13 Mar 2010, 14:25

Yes, I am using SDM. :mrgreen:

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daniel_reetz
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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by daniel_reetz » 13 Mar 2010, 15:35

Then your camera behavior is normal.

SDM was designed for stereo photography. In stereo photography, taking the two pictures at the exact same instant is very important. So you use one pulse to "prime" the cameras for shooting. Then you use a second pulse to fire them. Try it with your rig. If you do one short tap on your button, the cameras will "prime". Tap again, and they'll fire.

The alternate, as you've discovered, is to hold the button for a long time. On my portable rig, I have a microcontroller that holds the button for exactly 1.5 seconds, so it reliably triggers both cameras every time.

I think there are menu options in SDM to change this behavior -- dig around a bit. And disable your autofocus, man! Not sure how to do it on this model. EDIT: I see you have this under control

Good luck! Great progress on this machine!

jakegaisser
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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by jakegaisser » 14 Mar 2010, 03:32

Thanks! I did not realize that was normal behavior. What components do you use for your micro-controller? do you have a schematic for building it? I would like a similar solution.

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daniel_reetz
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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by daniel_reetz » 14 Mar 2010, 09:11

It's just a stock Arduino, almost no building necessary.

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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by jakegaisser » 15 Mar 2010, 17:07

I am now powering the cameras and usb remote using an ATX computer power supply, I used the 3.3v source to feed the cameras and the 5v source to feed the remote. Two days worth of scanning, no issues yet.

OH and for plugs that fit into the cameras DC jack, I brought my camera to the thrift stores and found a couple car cell phone chargers that had the same jack size, and I just cut off the car charger part. (Used a VOLT meter to check the continuity of the 2 wires, I sent the 3.3v to center of the jack, and ground to the outside.)


I will be working on the automatic picture taking soon, so that I don't have to push a button.

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daniel_reetz
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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by daniel_reetz » 15 Mar 2010, 17:42

How are you getting the ATX power supply to turn on?

I think that's a really exciting development. ATX power supplies are everywhere. Getting the cameras powered and triggered off one scrap source will save money and time, I think.

jakegaisser
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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by jakegaisser » 15 Mar 2010, 17:46

I put a switch between pin 14 and 15 on my 20 pin ATX supply: http://pinouts.ru/Power/atxpower_pinout.shtml

you can also just short the two pins with a piece of wire.

Also I should note that some cheapo power supplies can be scarry and have fluctuating voltages. my supply is an ANTEC which is a high quality brand.

You could use a cheaper Power supply, but if you do I would hook up a voltmeter to the 3.3v and 5v sources and monitor them a bit to make sure they are in spec and not fluctuating.

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Re: JakeGaisser Scanner: 1x1, 2x4, furniture, glass

Post by jakegaisser » 15 Mar 2010, 17:50

>Q2: Computer ATX power supplies have a 3.3 V line. I have some old
>unused power supplies (and I can buy them nearby for $5). Can I use an
>ATX power supply to power the camera?

It'd be awefully bulky, but it's likely you can. However,
you should put a certain minimum load on the 5V rail to
stabilize the output. A 2 Ohm 10W power resistor should be
sufficient, connected between the 5V rail and ground- either
on one of the leads or inside the PSU if you feel competent
inside a power supply to figure that out- if not I'm not
going to tell you how to do it, but it isn't hard, just
fiddly taking the thing apart to do it.
that is a post from this thread: http://www.tomshardware.com/forum/33879 ... wer-supply

I did not have a power resistor and did not really deem it necessary since the power supply is a nice quality unit. but a power resistor like he mentions would be a good idea :)

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